The purpose of this research project is to evaluate monoclonal antibodies capable of permitting increased diagnostic accuracy in histopathology or of identifying significant prognostic groups. Monoclonal antibodies obtained from several sources will be screened against a panel of normal human tissues and selected neoplasms of variable histogenesis and degrees of differentiation. A bank of frozen tumors maintained at -80~C at the Division of Anatomic Pathology at the City of Hope will be the primary source of material. In addition, paraffin-embedded tumors fixed in absolute alcohol, buffered formalin, and other fixatives will also be tested, if warranted by preliminary study, and compared with the results obtained from frozen sections. Transmission electron microscopy and electron microscopy immunochemistry will be done on selected cases of diagnostic difficulty. Various immunohistochemical methods will be initially employed on frozen and paraffin-embedded tissues fixed in various fixatives to maximize selection of the optimal handling for each antigen/antibody. Antibodies which after this screening show tissue or tumor discriminatory capacity will be tested against a larger group of well-characterized neoplasms of appropriate type depending on the specificity shown by prior tests. The results of the immunohistochemical studies will be correlated with the histopathologic diagnosis, tumor grade, stage of disease, response to therapy, survival, and other prognostic parameters of specific significance for the neoplasms involved. (2)